How to set color of templated image in NSTextAttachment

It seems that there's a bug in UIKit. There's a workaround for that ;]

For some reason you need to append empty space before image attachment to make it work properly with UIImageRenderingModeAlwaysTemplate.

So your snippet would look like that (mine is in ObjC):

- (NSAttributedString *)attributedStringWithValue:(NSString *)string image:(UIImage *)image {    NSTextAttachment *attachment = [[NSTextAttachment alloc] init];    attachment.image = image;    NSAttributedString *attachmentString = [NSAttributedString attributedStringWithAttachment:attachment];    NSMutableAttributedString *mutableAttributedString = [[NSMutableAttributedString alloc] initWithAttributedString:[[NSAttributedString alloc] initWithString:@" "]];    [mutableAttributedString appendAttributedString:attachmentString];    [mutableAttributedString addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:0] range:NSMakeRange(0, mutableAttributedString.length)]; // Put font size 0 to prevent offset    [mutableAttributedString addAttribute:NSForegroundColorAttributeName value:[UIColor whiteColor] range:NSMakeRange(0, mutableAttributedString.length)];    [mutableAttributedString appendAttributedString:[[NSAttributedString alloc] initWithString:@" "]];    NSAttributedString *ratingText = [[NSAttributedString alloc] initWithString:string];    [mutableAttributedString appendAttributedString:ratingText];    return mutableAttributedString;}

I have good experience with using the library UIImage+Additions when tinting UIImage instances. Specially check section IV.

If adding a third-party library is not an option, here is something to get you started:

- (UIImage *)colorImage:(UIImage *)image color:(UIColor *)color{    UIGraphicsBeginImageContextWithOptions(image.size, NO, [UIScreen mainScreen].scale);    CGContextRef context = UIGraphicsGetCurrentContext();    CGContextTranslateCTM(context, 0, image.size.height);    CGContextScaleCTM(context, 1.0, -1.0);    CGRect rect = CGRectMake(0, 0, image.size.width, image.size.height);    CGContextSetBlendMode(context, kCGBlendModeNormal);    CGContextDrawImage(context, rect, image.CGImage);    CGContextSetBlendMode(context, kCGBlendModeSourceIn);    [color setFill];    CGContextFillRect(context, rect);    UIImage *coloredImage = UIGraphicsGetImageFromCurrentImageContext();    UIGraphicsEndImageContext();    return coloredImage;}

This will make a UIImage go from:

To

Update: Swift version:

extension UIImage {    func colorImage(with color: UIColor) -> UIImage? {        guard let cgImage = self.cgImage else { return nil }        UIGraphicsBeginImageContext(self.size)        let contextRef = UIGraphicsGetCurrentContext()        contextRef?.translateBy(x: 0, y: self.size.height)        contextRef?.scaleBy(x: 1.0, y: -1.0)        let rect = CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height)        contextRef?.setBlendMode(CGBlendMode.normal)        contextRef?.draw(cgImage, in: rect)        contextRef?.setBlendMode(CGBlendMode.sourceIn)        color.setFill()        contextRef?.fill(rect)        let coloredImage = UIGraphicsGetImageFromCurrentImageContext()        UIGraphicsEndImageContext()        return coloredImage    }}

I use this NSMutableAttributedString extension for Swift.

extension NSMutableAttributedString {    func addImageAttachment(image: UIImage, font: UIFont, textColor: UIColor, size: CGSize? = nil) {        let textAttributes: [NSAttributedString.Key: Any] = [            .strokeColor: textColor,            .foregroundColor: textColor,            .font: font        ]        self.append(            NSAttributedString.init(                //U+200C (zero-width non-joiner) is a non-printing character. It will not paste unnecessary space.                string: "\u{200c}",                attributes: textAttributes            )        )        let attachment = NSTextAttachment()        attachment.image = image.withRenderingMode(.alwaysTemplate)        //Uncomment to set size of image.         //P.S. font.capHeight sets height of image equal to font size.        //let imageSize = size ?? CGSize.init(width: font.capHeight, height: font.capHeight)        //attachment.bounds = CGRect(        //    x: 0,        //    y: 0,        //    width: imageSize.width,        //    height: imageSize.height        //)        let attachmentString = NSMutableAttributedString(attachment: attachment)        attachmentString.addAttributes(            textAttributes,            range: NSMakeRange(                0,                attachmentString.length            )        )        self.append(attachmentString)    }}

This is how to use it.

let attributedString = NSMutableAttributedString()if let image = UIImage.init(named: "image") {    attributedString.addImageAttachment(image: image, font: .systemFont(ofSize: 14), textColor: .red)}

You can also change addImageAttachment's parameter image: UIImage to image: UIImage? and check the nullability in extension.